Device for targeted, catherized delivery of medications

ABSTRACT

Apparatus and method for catheterized delivery or infusion of medication and anaesthesia are disclosed. The perforating catheter is first used to perforate the periodontal ligament and/or the cortical plate of bone tissue, and is then left in place and used as a catheter for insertion of a hypodermic needle of smaller gauge to deliver medication or anaesthesia to a target area. The perforator is a bevelled needle for drilling into the ligament or bone tissue. For drilling, the device comprises an adaptor which transmits the rotational movement from a dental hand piece or the like to the bevelled needle. A cap is also included for protecting the bevelled needle during storage of the device. The adaptor may have a rod which extends axially into the bevelled needle when the device is assembled for drilling. The rod is used to prevent the debris resulting from drilling from blocking the passage in the bevelled needle. As well, the rod reinforces the needle and maintains the alignment between the perforator and the adaptor for improved drilling efficiency.

[0001] This invention is a continuation-in-part patent application to09/255,442 filed Feb. 22, 1999 which is a continuation of patentapplication Ser. No. 09/022/314 filed Feb. 11, 1998 which is acontinuation of patent application Ser. No. 08/471372, now issued asU.S. Pat. No. 5,762,639.

FIELD OF THE INVENTION

[0002] The present invention provides for a simple method and device forinfusing or injecting medication; it is applicable to medical or dentaland the like procedures. More particularly, the invention is directed tocatheterized delivery of anesthesia and other medication. Moreparticularly still, it is directed to catheterized delivery of dentalanaesthetic to a targeted nerve and to an apparatus for such delivery.

BACKGROUND OF THE INVENTION

[0003] There are a variety of methods currently in use for providinglocal anaesthetic in dentistry. These methods and apparatuses howeverall have disadvantages, either being difficult for practitioners toperform or painful and unpleasant to the patient.

[0004] An example of a method used currently in dentistry is theinfiltration method, whereby a local anaesthetic solution is injectedinto the soft tissue of gingiva. In doing so, the solution eventuallypasses through the cortical plate affecting the nerve bundle enteringthe tooth. Disadvantages of this method include the delay of onset ofanaesthesia after the injection and, in most cases, ballooning of theinjected tissue. As well, there is an extended period of time forrecovery of the tissue until return to normal condition.

[0005] Another method which is currently used is the regional blockmethod whereby an anaesthetic solution is injected locally in proximityto the nerve trunk as it enters the bone. Disadvantages of thisprocedure are that it is extremely difficult to locate the nerve trunk,there is discomfort to the patient and a delay for the anaesthetic totake effect. As in the case of the infiltration method, this methodnecessitates a long recovery period for tissue to return to normal.

[0006] At present, two types of apparatus have been used to performintra-osseous anaesthesia. These are surgical burs used to perforate thecortical plate and the villet injectors.

[0007] The use of a surgical bur has disadvantages in that burs areexpensive and they have to be sterilized between uses or a new bur usedeach time. In addition, the method is slow, requiring the attachedgingiva and periosteum to be anaesthetized before the cortical plate isperforated. The villet injector is an apparatus that serves both as aperforator and injector. It uses specially designed needles rotated by aconventional dental motor. A disadvantage of this device is that theneedle often becomes clogged with pulverized bone which obstructs thepassage in the needle and prevents injection of the anaestheticsolution. It is generally difficult to remove the clogging material fromthe needle and often the use of a second needle is necessary. Otherdisadvantages of this method include the initial capital cost of theinstrument purchase, and the cost of the needles which are somewhatexpensive. In addition, the design of the instrument makes access tovarious parts of the mouth difficult and sometimes impossible.

[0008] Intra-osseous and targeted root-canal nerve anaesthesia have notbecome popular for the reason that there has not been a practicaltechnique of making the injections successfully. For example, there hasbeen a general belief that this method is radical and to be restored toonly if nerve block and infiltration anaesthetic do not accomplish thedesired result. However, intra-osseous and targeted injections producepositive, more profound anaesthesia and could be made with less painthan either of the other types according to the present invention.

[0009] Targeted anaesthesia has several advantages over prior art nerveblock or infiltration methods. There is no feeling of numbness in thetongue, cheek, or lips during or after the injection and there is noafter-pain. The anaesthetic is profound and acts immediately alleviatingthe necessity of waiting for the anaesthetic to take effect as with thenerve block and infiltration methods. Furthermore, as only a few dropsof anaesthetic are injected, there is no feeling of faintness orincreasing of the pulse rate.

[0010] To achieve targeted anaesthesia one must gain access, ifintra-osseous, to the cancellous bone by going through the corticallayer; or to the bottom of the tooth, if root-canal targeted anaesthesiais desired. Because of instant anaesthesia and profound pulpalanaesthesia, there is a much greater control over the region one wishesto anaesthetize, resulting in a much smaller dose of anaesthetic; aswell as, of course, other medication, where applicable.

[0011] U.S. Pat. No. 5,173,050 (Dillon) discloses a dental apparatus forperforating the cortical plate of human maxillary and mandibular bones.The apparatus of Dillon comprises a metal needle moulded into a plasticshank. The shank is being formed with means for cooperation with adental hand piece for transmitting the rotational movement to theneedle. The needle used for drilling is solid and has a sharp bevelledfree end. The apparatus described by Dillon is disposable.

[0012] However, the device disclosed in Dillon's patent cannot be usedas a catheter for injecting anaesthetic by inserting a hypodermic needlethrough the drilling needle. As well, the device disclosed by Dillon isnot provided with means for blocking entry of bone debris into theneedle passageway. In addition, the direct connection between the handpiece and the perforator does not provide for a safe and reliablebarrier against bacteria passing from the needle to the hand piece.

[0013] U.S. Pat. No. 3,534,476 (Winters) discloses a drilling andfilling root canal apparatus. The drilling is performed by a drillhaving a central bore. The depth of the root canal is determined inadvance and a stop is placed on the drill to limit the depth ofdrilling. The device is provided with a flexible rod which is pushedinto the root canal so that the drill is directed along this road tofollow the contour of the canal so that resulting bore will have anuniform diameter which is free of shoulders or ledges. The apparatusdisclosed by Winters is concerned with enlarging the root canal afterthe nerve has been extracted. This apparatus is not used for injectingmedication in close proximity to a targeted area for treatment oranaesthetic.

[0014] U.S. Pat. No. 4,944,677 (Alexandre) discloses a smooth hollowneedle with a bevelled point for drilling a hole into the jawbone nearthe apex of the tooth to be anaesthetized. Thereafter, the drillingdevice 13 removed from the jaw, and a hypodermic needle of substantiallythe same gauge is inserted into the hole and anaesthesia is injected.Thus, there is no cathetized delivery of medication, with the attendantdisadvantage that the pre-drilled hole may be difficult to locate wheninserting the hypodermic needle.

[0015] One significantly older United States patent that is discussed byAlexandre (above) is U.S. Pat. No. 2,317,648 (Siqveland) granted in1943. In addition to the disadvantage mentioned by Alexandre, the factthat Siqveland teaches use of threaded sleeve which penetrates the boneduring drilling and is left (screwed) in the bone to serve as a guidefor insertion of the actual injection needle. Due to the cost of such adevice, it cannot be made disposable; but more importantly, for thethreaded sleeve to be securely fastened in the bone it would have torotate at a much slower speed than the drill (as in Siqveland) or thedrilling catheter (as in the present invention).

[0016] Several other U.S. patents such as U.S. Pat. No. 5,332,398 in thename of Miller, and U.S. Pat. No. 4,969,870 in the name of Kramer havefollowed the teaching of Siqveland wherein the catheter is at leastsomewhere along its outer periphery threaded, or designed to implantitself fixedly within the bone it is being disposed in; Furthermore,designs of this type require slowly turning the drilling shaft (orcatheter sleeve) into the bone until resistance is encountered at whichpoint the catheter is determined to be in place.

[0017] Over the past 50 year or so, and at least since the invention ofSiqveland, patented in 1943, devices and processes for intraosseousanesthesia have been developed and refined. However, heretofore, noother inventors have provides a useful, workable convenient andinexpensive solution that affords all of the benefits provided by thisinvention. For example, non of the prior art devices allow a motorizedhandpiece to drive a small intraosseous catheter/drill having arod/drill therein wherein the device can be placed by drilling at highor slower speeds and removed by simple withdrawal by pulling out thecatheter. Most of the effort in this field had been directed towardlonger term delivery of medication wherein the catheters have had somemeans of latching into the bone for more permanent placement.Furthermore, the instant invention does not suffer from may of thedrawbacks of inserting the needle/drill into the bore being cut by theend tip of the drill, since the outside walls of the needle/drill are ofa uniform diameter and non-varying. With the long-felt want of thisdevice, in the past decade in view of the many publications in thisfield, no such optimal device has been suggested.

[0018] In contrast to the prior art, the instant invention provides adual purpose perforator which includes a needle/sleeve that serves as arelatively high-speed drill bit and which serves as a catheter that isremovable by withdrawing it by pulling it out, and not by unscrewing it.The perforator has a substantially uniform outer diameter and has asmooth non-threaded outer surface; preferably, the catheter is a largergauge needle than the removable rod contained within which may also bein the form of a beveled needle for preventing bone, skin and debrisfrom entering the catheter during entry into the bone. A hypodermicneedle of same gauge as the rod is later placed in the catheter afterthe rod is removed.

[0019] Advantageously, the beveled end of the rod assists the cutting ofthe opening into the bone along with the perforator as they are bothrotated by the dental hand piece they are coupled therewith.

[0020] To our knowledge, there are no prior art patents, which teach theuse of a perforator having a hypodermic needle-like cutting tool whereinthe outer diameter is uniform allowing both precise cutting of a smallhole, and allowing easy removal by simply pulling the device out withoutunthreading, wherein the perforator has an upper end adapted to beconnected to a motorized dental hand piece; and, wherein the perforatorhas a rod therein which turns with the perforator needle-like cuttingtool assisting in preventing debris from entering the perforator; andwherein the rod is itself a needle-like cutting tool assisting in thecutting of the opening.

[0021] To our knowledge, aside from the parent patent application, nowissued as U.S. Pat. No. 5,332,398, there are no prior art patents, whichteach the use of a perforator having a hypodermic needle-like cuttingtool wherein the outer diameter is uniform allowing both precise cuttingof a small hole, and allowing easy removal by simply pulling the deviceout without unthreading, wherein the perforator has an upper end adaptedto be connected to a motorized dental hand piece; and, wherein theperforator has a rod therein which turns with the perforator needle-likecutting tool assisting in preventing debris from entering theperforator; and wherein the perforator serves as a catheter foraccommodating a hypodermic needle having a same outer diameter as therod, after the catheter is inserted into the bone.

[0022] It is the belief of the inventor, that this novel method andcombination of elements will eventually change the way in which manydentists infuse medication and local anesthesia.

[0023] Unlike the prior art catheters the catheter drill of the instantinvention will not bind or increase its resistance against the drillinghand piece as it is drilling into the bone. The uniform outer diameterallows the drill/needle to cut without binding and acting as aself-tapping hollow screw.

SUMMARY OF THE INVENTION

[0024] The present invention endeavours to mitigate the problems anddisadvantages of delivering dental anaesthetic encountered with theprior art methods and devices.

[0025] The present invention provides a perforator having a centralpassage, which perforator then remains in place as a catheter forallowing a hypodermic needle to be inserted through the passage todeliver the desired medication. The preferred apparatus is provided withmeans for obstructing the entry of debris in the perforator's passage.

[0026] In accordance with the invention, there is provided a device forperforating the periodontal ligaments, cortical plate or small bones,and the like and for injecting substances at a predetermined site,comprising:

[0027] perforator for drilling a hole into the ligament, bone or tissue,wherein said perforator is provided with an inner passage to form acatheter adapted to remain in the hole for directing a hypodermic needleto the predetermined site; and

[0028] an adapter for coupling to an end of the perforator and forlatching a latching-type powered dental handpiece thereto and fortransmitting rotational movement from the powered dental handpeice tosaid perforator, the perforator having a drilling needle extending froman end thereof, the drilling needle having a uniform outer diameter anda smooth non-varying outer surface allowing removal once inserted intothe periodontal ligaments, cortical plate or small bones and the like bywithdrawing the needle by pulling backwards along a line defined by alongitudinal axis of the inserted drilling needle; the adapter forcoupling with the perforator in a locking engagement such thatrotational motion imparted to the adapter, rotates the perforator whenthe adapter is coupled with the perforator, the adapter having an upperend having a driving shank extending along a rotational axis forremovably engaging the powered dental hand tool, the adapter having arod sized to be accommodated within the perforator and sized to fit intoa passage in said drilling needle at a lower end thereof.

[0029] In a further aspect, the rotary drive shaft comprises an axialrod adapted to be inserted into the hollow drilling catheter whenengaging it.

[0030] According to another aspect of the present invention, there isprovided a device for perforating the periodontal ligaments, corticalplate of small bones, and the like, for injecting substances at apredetermined site, comprising:

[0031] a perforator for drilling a hole into the ligament, bone ortissue, wherein said perforator is provided with an inner passage toform a catheter adapted to remain in the hole perforated for directing ahypodermic needle to said predetermined site, and an adaptor forlatching in a latching-type powered dental handpiece for transmittingrotational movement to said perforator, the adapter having a rod at anend thereof sized to be disposed within the perforator inner passage.

[0032] The catheterized intra-osseous delivery system of the presentinvention comprises a perforator with a bevelled drilling needle that isused as a drill and a catheter. The needle is attached at one end to aplastic or metal body. For drilling, the body is attached to a matchingadaptor provided with a driving shank which is rotated by a conventionalcontra angle or straight dental hand piece. Then, the perforator is usedas a catheter, whereby a hypodermic needle is inserted through thedrilling needle without losing access to the already perforated bone.

[0033] In the preferred form of the invention the apparatus isdisposable. Before disposal, the perforator receives a cap over theneedle for protection against accidental contamination of environment.

[0034] The present invention also provides a method of medicaltreatment, comprising the steps of: inserting a catheter, at a point inthe gingival sulcus between outer tooth surface and marginal gingiva, orthrough gingiva and cortical plate, to a predetermined depth; andinjecting medication or anaesthesia through said catheter.

[0035] Advantageously, the system of the present invention provide userswith a more secure and less painful method and device for direct accessfor injecting medication to a target area into the cortical plate of thebone.

[0036] In addition, the system facilitates and adds a level of securitypreviously unavailable for the anaesthetic in that it has a sure andimmediate effect.

[0037] Another advantage of this system is that it provides benefits tothe dentists by facilitating the use of a low cost, disposable device.

[0038] Still another advantage of this invention is that the risk ofcontamination is lower than with the current devices. This is becausethe device is disposable and because the risk of the dental equipmentused with the device of the invention becoming contaminated is low.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] These and other features of the invention will become moreapparent from the following description of the preferred embodiments, inwhich reference is made to the appended drawings, wherein:

[0040]FIG. 1 illustrates an exploded view of the device showing thecomponent parts and their inter-relationship;

[0041]FIG. 2A illustrates the device assembled for drilling;

[0042]FIG. 2B Illustrated a longitudinal cross-section through thedevice illustrated in FIG. 2A, taken along line A-A of FIG. 2A;

[0043]FIG. 3 shows a detailed view of the area marked on FIG. 2B;

[0044]FIG. 3B shows a detailed view of the rod-needle inserted in theperforator cutting/drilling-needle inserted in a different orientationthan in FIG. 3;

[0045]FIG. 4 is a cross-sectional view of the body of the perforatortaken along lines B-B of FIG. 2;

[0046]FIG. 5 is a cross-sectional view of the adaptor body;

[0047]FIG. 6 is a cross-sectional view of the cap;

[0048] FIGS. 7A-7C illustrate the method according to the invention,FIG. 7A shows the device drilling, in the bone tissue; FIG. 7B shows theperforator inserted into the bone tissue and the adaptor de-coupled; andFIG. 7C shows the perforator inserted into the bone tissue as a catheterand a hypodermic needle set for delivering an injection;

[0049]FIG. 8 illustrates another embodiment of the invention;

[0050]FIG. 9 illustrates an alternative method of delivery medication totreat a root-canal nerve;

[0051]FIG. 10 illustrates from a plan view the point of catheterinsertion for the alternative method shown in FIG. 9;

[0052]FIG. 11 is a perspective, exploded view of the parts of analternative embodiment of the invention wherein the catheter and adaptercan be temporarily locked while drilling occurs;

[0053]FIG. 12 is a sectional elevation of the same catheter assembly;and,

[0054]FIG. 13 is a plane view of an additional, optional component ofthe assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0055]FIG. 1 illustrates an exploded view of the device showing thecomponent parts and their inter-relationship. The device comprises aperforator 1, an adaptor 3 and a cap 5.

[0056] The perforator 1 has a bevelled drilling needle 7 which is usedboth as a drill and a catheter. Needle 7 is bevelled at both ends, asbetter shown on FIG. 2B. The first end 9 is formed as a drilling tip inthat it has cutting teeth along the edge, as shown in FIG. 3. The secondend 11 is bevelled for receiving and directing the needle of ahypodermic syringe and for easy coupling with the adaptor 3, as will beseen later.

[0057] A flange 13 is fixed on the needle about the second end 11, sothat the needle passes along the geometrical axis of the flange 13. Theflange 13 is manufactured or moulded of a plastic or other material, andit has a generally cylindrical outer shape. This shape is preferred asthe flange 13 rotates together with the needle 7 for drilling.Variations of the shape illustrated in the attached drawings may also becontemplated.

[0058] The flange 13 is adapted for receiving cap 5 at one end and forcoupling with the adaptor 3 at the other end. As an example, a collar 15may be provided on the flange 13 so that the cap 5 holds over the collar15 when pressed. The cap 5 is needed to protect and cover the tip 9 ofthe needle 7 before use and when the device is disposed of.

[0059] For ease of manipulation the internal diameter of the cap 5 andthe external diameter of the collar 15 should be as large as isreasonable and preferably between 10 to 20 times greater than thediameter of the needle 7. Another advantage of the collar 15 is that itprovides a stop to limit the depths of penetration of the needle 7 (thedepth of penetration of the needle 7 is, therefore, termed the drillinglength, as opposed to the remaining length of the needle 7, which istermed the attachment length). The flange 13 is shaped to form an inneraxial shaft 17 projecting from the centre of the collar 15, and a femaleconnector 19 for coupling with a corresponding male connector providedin the adaptor 3.

[0060] The coupling between the perforator and the adaptor isillustrated on FIGS. 2B, 4 and 5. FIG. 2B shows a longitudinal sectionof a female connector 19 provided in the flange 13 and a male connector21 provided in the adaptor 3. FIG. 4 illustrates a cross-section of anexemplary female connector 19, while FIG. 5 shows a cross-section of thecorresponding male connector 21. The male connector is provided withradial ribs 23, extending towards the centre but not meeting to leaveroom for the central shaft 17, while corresponding grooves 25 areprovided in the female connector, alternating with islands 20. Thefemale connector is also formed with a clearance ring 22 foraccommodating the thickness of the body 29 of the adaptor.

[0061] The tubular shaft 17 forms a reinforced passage for drillingneedle 7. The shaft also provides enough contact surface between thedrilling needle and the body to ensure that these two parts rotatetogether during drilling. As could be seen on FIG. 2B, end 11 of theneedle is bevelled and extends a little over the shaft 17, but there isa clearance between the tip of end 11 and the male connector when thedevice is assembled for drilling.

[0062] When rotated, the drilling needle 7 penetrates in the bone tissuethrough gingiva or ligament and drills a hole with the cutting tip 9.The perforator 1 may remain in place as a catheter, with the drillingneedle inserted into the bone. Then, a hypodermic needle may beintroduced through the passage of drilling needle 7 to inject amedicament directly into the bone. Therefore, the drilling needle 7 isselected to have a wide enough passage for allowing a hypodermic needlewith a smaller gauge to be inserted through needle 7.

[0063] The adaptor 3 has several important functions. Firstly, theadaptor conveys the rotational movement from a dental hand piece or thelike to the perforator. As well, the adaptor is provided with means forblocking bone debris for entering into the syringe passage and alsoaligns and reinforces the needle 7 during drilling. In the preferredembodiment of this invention is it important that the adapter be coupledwith the dental hand tool which dives the adapter about its longitudinalaxis. It is also important that the adapter conveys its rotationalmovement from the dental hand piece to the perforator 3. By providingthis novel arrangement, after the perforator is inserted into the bone,where it is to remain, all that is required is that the adapter with thedental handpiece be removed from the perforator. Hence the order ofdental hand piece driving the adapter including the rod 27 which in turndrives the perforator and its drilling needle is important in thepreferred embodiment.

[0064] The adaptor includes a rod 27, a body 29 and a shank 31.

[0065] Body 29 includes male connector 21 which is formed, as indicatedabove, with longitudinal ribs 23 which couple with grooves 25 of thefemale connector 19 for driving needle 7. The shank 31 extends along theaxis of the adaptor and is formed with a joint 33 for attachment with acontra-angle or straight hand piece. The shank 31 has a groove 35 and acut-out 37 to fix the shank in place in the known manner. Generally, theshank transmits to the needle 7 the rotational movement from the handpiece.

[0066] The shank 31 also acts as a barrier for contamination, at it isgenerally thought that bacteria is reluctant to change direction, andthere are a plurality of 90° angles between the tip 9 of drilling needle7 and the joint 33.

[0067] The rod 27 has the diameter and length selected in accordancewith the size of needle 7. The rod 27 is fixed in the geometrical centreof body 29 so as to readily penetrate into the hollow passage of theneedle, when the device is assembled for drilling. When the rod 27 isinserted within the needle passage, it advances through the length ofthe needle up to the bevelled end, as shown on FIGS. 2A and 3 and 3B indotted lines. In this way, the debris from drilling cannot penetrate toblock the needle passage. In addition, the rod gives additionalrigidity, strength and alignment to needle 7 during drilling. The rodalso Advances through the a portion of the shank as is illustrated inFIG. 2B in dotted lines. Furthermore, the rod which can itself be in theform of a needle similar to the hypodermic needle for delivery ofmedication, wherein the rod end is sharp and pointed, to assist in thedrilling process. By using standard hypodermic needle tubing for therod, the cost of the device can be minimized while gaining the benefitof the cutting tip. In manufacture, the cutting tip of the drillingneedle 7 and the rod can be cut at the same time to a desired length.

[0068]FIG. 8 illustrates an alternative embodiment of the presentinvention. In this variant, body 13 is provided with an internal threadwhile body 29 is provided with a matching external thread. By threadingone to the other and using the central rod 27 to align the two bodiestogether, the perforator could be driven by the hand piece in a similarmanner as in the variant disclosed above. Of course, the thread is goingin an opposite direction to the direction of rotation of the device foravoiding disconnection of the two bodies.

[0069] An alternative method of targeted delivery is shown in FIGS. 9and 10. The perforator 7 is inserted at a point 30 between teeth,parallel to the tooth 31 in treatment, and penetrates through gingivalsulcus 32 and ligament 33 to a depth near the entry of the nerve, arteryand vein bundle 34 through the bone 35 and into the tooth-root canal 36.This method of targeted delivery, say, of anaesthesia is suitable, whereperforating vertical to the tooth through gingiva and cortical bone isnot convenient or possible; as in the case of rear molars.

[0070] There are a variety of ways that this invention can be devisedbut the end result is to perform catheterized intra-osseous deliverysystem.

[0071] The device of this invention operates as follows:

[0072] First, a site for the injection is selected by the practitioner.The gingiva over the injection side is disinfected and topicallyanaesthetized. A small amount of anaesthetic solution is injected untilblanching of the tissue, and this will anaesthetize the gingiva and theperiosteum. The following operations are illustrated in FIGS. 7A, 7B and7C, and FIGS. 9 and 10.

[0073] As can be seen in FIG. 7A, the bevelled end 9 of the needle 7 isplaced against the gingiva and shank 31 is attached with joint 33 to acontra angle or to a straight dental hand piece. The adaptor andperforator are coupled for drilling.

[0074] The perforator should be held perpendicular to the corticalplate, or if not possible or convenient, it should be held vertical andparallel to the long axis of the tooth as shown in FIG. 9, having beeninserted between teeth as shown in FIG. 10. The perforator is thenoperated in small bursts of rotation from the hand piece untilresistance is no longer felt, as is well known to dentists.

[0075] Next, the adaptor 3 is removed from the engagement withperforator 1 by applying pressure to the body 13 with the fingers thuskeeping the needle 7 in the perforated cortical plate. This is shown inFIG. 7B.

[0076] The presence of the needle 7 in the cortical plate, or down theside of the tooth as in FIG. 9, allows an injection to be made withoutcomplicated manoeuvres to find the perforation in the case of floatinggingiva or the free or marginal gingiva. FIG. 7C illustrates the nextstep, namely how the injection needle is inserted through the perforator1 for delivering the anaesthetic solution required.

[0077] The last step is to remove the perforator 1 from the corticalplate and reinstall the cover cap 5 over the needle 7, then insert theadaptor to the perforator making the unit complete and disposable. Thecap 5 provides a means whereby the apparatus may be removed from thedental hand piece without any risk of the user being in contact withbody fluids which will be present on the needle after use. This isextremely important particularly since there may be a risk of contactingAids or Hepatitis should the user accidentally prick a finger with theneedle. It is therefore desirable that the cap should be of a hard orrigid rubber or plastic material not easily penetrated by the needle.Referring to FIG. 11 and 12, the catheter assembly comprises adisposable contamination protective cap or housing 10 which, in theassembled state, surrounds a hollow drilling needle or catheter 11,preferably of stainless steel, having a drilling tip 12 and anon-drilling end with an outwardly flaring end portion 13. The endportion is fixed, and preferably molded, within a cylindrical drivenflange 14 which is made of plastic material and is disposable along withthe needle.

[0078] The flange is adapted bo be driven by the drive means including adrive flange 16 which has a periphery matching radius of the flange 14,and which is integrally formed with a shaft 17 suitably dimensioned tofit into the handpiece of a standard dental drill; the diameter of thisshaft being preferably between 2.27 and 2.45 mm. Parts 16 and 17 mayeither be metal or plastic, and will also normally be considereddisposable. The flange 16 and shaft 17 have an axial bore into which issecured a rod 20 having a cutting tip (not shown) which projects fromthe flange 17 by an amount equivalent to the main drilling length of theneedle 11, and which prevents the needle from becoming blocked withdebris during operation.

[0079] The driven flange 14 and the drive flange 16 each have alongitudinal groove, indicated respectively at 14 a, 16 a. When all theparts are assembled, these grooves are occupied by a longitudinalinternal rib 21 in the cylindrical wall of the a locking sleeve 22. Thisis a thin-walled, disposable cap-type part, the cylindrical wall ofwhich is capable of substantially enclosing the two flanges 14 and 16,and having an upper end flange 22 a which, when the sleeve is fullyengaged with the two flanges 14 and 16, rests against the upper surfaceof the flange 16. The sleeve 22 serves to hold the flanges together, aswell as transmitting rotary motion from the drive to the driven flange.The sleeve is a push fit within the housing 10.

[0080] The parts are sold in the assembled condition as shown in FIG.12. For use the housing 10 is removed, the shaft 17 is fitted into adrilling machine, and a drilling proceeds in the normal way. Afterdrilling, the shaft 17 with flange 16, and rod 20 and sleeve 22, areremoved from the flange 14, and anaesthetic is then introduced throughthe needle 11 which then acts as a catheter.

[0081] All parts of the assembly are disposable after use.

[0082]FIG. 13 shows a further feature of this embodiment, namely aholder 30 which comprises a rod 30 a fixed at one end to part circularclip portion 30 b which is formed to encircle a circumferentiallygrooved central area 14 b of the flange 14. This holder may be placed inposition to hold the flange 14 after drilling has taken place, with itsrod 30 a lying along side of the patients mouth and preventingundesirable movement of the flange 14 during the injection step.

[0083] In summary, this invention provides particular advantages notsuggested in prior art devices. The provision of an adapter piece havinga rod at a lower end, a shaft at an upper end for coupling with amotorized dental handpeice, and an intermediate hub disposed between therod and the shaft wherein the hub has means for locking with a catheterhaving a drilling needle provides numerous advantages. The drillingneedle has a uniform outer diameter and can be withdrawn by simplypulling it out. The adapter is designed to prevent the drilling needlefrom becoming blocked during drilling and is designed to turn thedrilling needle when powered by the handpeice. More importantly, whenthe catheter has drilled the hole in the bone, the adapter can beremoved with the handtool leaving the catheter in place.

[0084] Numerous other embodiments can be envisaged without departingfrom the spirit and scope of the invention. For example, the end of therod can be provided with a cutting tip assisting the cutting needle indrilling the hole. Furthermore, the rod itself can be a square rod forengaging a complementary recess in the catheter opening. This embodimentwould allow the device to function even if the rod was partiallyextracted during the drilling of the hole as any portion of the squarerod could be used to drive the cutting needle.

[0085] Another embodiment this invention provides an automatic deliveryof fluid or medication to the catheter. Here, a medication injectiondevice comprises a housing for grasping by an operator, wherein thehousing has a distal end; a rotatable hollow drill bit mounted to thedistal end of the housing, wherein the drill bit includes a boretherethrough, and wherein the drill bit is suitable for intraosseousdrilling; means disposed in the housing for rotating the drill bit; andfluid dispensing means including a fluid reservoir stationarily mountedin the housing and means for supplying a controlled dose of medicationfluid for intraossaous injection through the bore of the drill bit. Yetstill further, a removable rod is inserted into the drill bit forpreventing material from blocking the catheter. In order to preventdebris from entering the drilling needle, a solid or hollow rod isdisposed within the drill bit which is spring loaded in the head of thehousing opposite the drill bit. The rod under spring tension is removedby removing a cap on the head of the handpiece.

What is claimed is:
 1. A device for perforating the periodontalligaments, cortical plate or small bones, and the like and for injectingsubstances at a predetermined site, comprising: perforator for drillinga hole into the ligament, bone or tissue, wherein said perforator isprovided with an inner passage to form a catheter adapted to remain inthe hole for directing a hypodermic needle to the predetermined site;and an adapter for coupling to an end of the perforator and for latchinga latching-type powered dental handpiece thereto and for transmittingrotational movement from the powered dental handpiece to saidperforator, the perforator having a drilling needle extending from anend thereof, the drilling needle having a uniform outer diameter and asmooth non-varying outer surface allowing removal once inserted into theperiodontal ligaments, cortical plate or small bones and the like bywithdrawing the needle by pulling backwards along a line defined by alongitudinal axis of the inserted drilling needle; the adapter forcoupling with the perforator in a locking engagement such thatrotational motion imparted to the adapter, rotates the perforator whenthe adapter is coupled with the perforator, the adapter having an upperend having a driving shank extending along a rotational axis forremovably engaging the powered dental hand tool, the adapter having arod sized to be accommodated within the perforator and sized to fit intoa passage in said drilling needle at a lower end thereof.
 2. A device asdefined in claim 1, wherein the rod has an cutting end for cuttingsimultaneously with the drilling needle.
 3. A device as defined in claim2 wherein the rod is a drilling needle having a smaller diameter thanthe drilling needle on the perforator.
 4. A device as defined in claim 3wherein the rod has an outer diameter that is the same as an outerdiameter of the hypodermic needle.
 5. A device as defined in claim 3wherein the rod has an outer diameter that is the same as an outerdiameter of the hypodermic needle and wherein the rod has a tip at itsend that is the same as the tip of the hypodermic needle.
 6. A device asclaimed in claim 1, wherein said drilling needle has a drilling lengthand an attachment length, and a passage sized to accommodate thehypodermic needle of a smaller gauge.
 7. A device as claimed in claim 6,wherein said drilling length ends with a cutting edge.
 8. A device asclaimed in claim 7, wherein said cutting edge of the drilling needle isbevelled and where the rod has a cutting edge that is bevelled.
 9. Adevice as claimed in claim 7, wherein said cutting edge is provided withcutting teeth therealong.
 10. A device as claimed in claim 1 whereinsaid perforator is provided with means for receiving and securing aprotective cap over said cutting needle.
 11. A device as claimed inclaim 10, wherein said means for receiving and securing comprises a discentered about said needle and fixed on said first body for receivingsaid protective cap.
 12. A device as claimed in claim 1, wherein saidrod comprises: a anchoring part incorporated and fixed into said shank,for driving said rod to rotate with said shank.
 13. A rotatable drillingdevice for use in injecting medication, said rotatable drilling devicecomprising: a rotatable hollow drill bit, wherein the rotatable hollowdrill bit includes a catheter hub and a needle having a uniformnon-varying outer diameter extending outwardly from an end of thecatheter hub, wherein the needle has a sharpened tip, wherein therotatable hollow drill bit has a bore extending through the hub andneedle, and wherein an end of the hub opposite the needle has an openingthrough which medication can be introduced into the bore; and an adapterhaving a rod at a lower end for removabley insertion in the bore of therotatable hollow drill bit, wherein the rod when inserted into the boreextends through the bore of the rotatable hollow drill bit to the tip ofthe needle, the rod and the hollow drill bit being coupled together inlocked engagement when the rod is inserted into the bore of therotatable hollow drill bit, the adapter having an end adapted to couplethe rod to handpiece for rotation therewith.
 14. A device as defined inclaim 13, wherein the rod has a cutting tip for cutting simultaneouslywith the hollow rotatable drill bit.
 15. A device as defined in claim13, wherein the adapter has a hub for coupling with the catehter hub.16. A device as defined in claim 13, wherein the drill bit is ahypodermic needle having the cutting tip is sized to receive ahypodermic needle for delivery of medication.
 17. A method of providinginter-osseous medication to a patient comprising the step of: a)providing a hollow drilling catheter means for penetrating ligament,tissue or bone and adapted to remain in place after drilling, thecatheter means having a drilling hypodermic needle having a uniformnon-varying outer diameter and a cutting tip; and means for engaging anddisengaging the drilling catheter to and from a rotary drive shaft; and,disposing within the drilling needle an axial rod which engages thecatheter so that by rotating an upper end of the rod the drilling needleis rotated; coupling an upper end of the rod with a motorized hand tool;engaging the motorized hand tool to drilling a hole with the catheter ina desired site of the patient; and, removing the rod; inserting ahypodermic needle into the catheter and into the drilling needle in thedesired site, and injecting medication thereto from the hypodermicneedle; and, removing the catheter by pulling the catheter along itslongitudinal axis backward away from the patient.
 18. A method asdefined in claim 17, wherein the rod has a cutting tip and wherein therod is rotated with the drilling needle and wherein the rod and thedrilling needle drill the hole simultaneously.
 19. A device forperforating the periodontal ligaments, cortical plate of small bones,and the like, for injecting substances at a predetermined site,comprising: a perforator for drilling a hole into the ligament, bone ortissue, wherein said perforator is provided with an inner passage toform a catheter adapted to remain in the hole perforated for directing ahypodermic needle to said predetermined site, the perforator having ahub at an upper end and a drilling needle at a lower end thereof; and,an adaptor having a complementary hub for mating with the hub of theperforator and for locking therewith, such that in locking engagementrotation of the adapter hub rotates the perforator hub, the adapterhaving an upper end for latching with a latching-type powered dentalhandpiece for transmitting rotational movement to said perforator, theadapter having a rod at an end thereof sized to be disposed within theperforator inner passage, the rod, and the drilling needle being rotatedsimultaneously when the powered dental handpiece rotates the upper endof the adapter.
 20. A rotatable drilling device for use in injectingmedication, said rotatable drilling device comprising: a rotatablehollow drill bit adapted for mounting in a a drill, wherein therotatable hollow drill bit includes a hub and a needle extendingoutwardly from an end of the hub, wherein the needle has a sharpenedtip, wherein the rotatable hollow drill bit has a bore extending throughthe hub and needle, and wherein an end of the hub opposite the needlehas an opening through which medication can be introduced into the bore,wherein the hub further includes an adapter means for coupling the hubto the drill for rotation therewith; and a rod removably inserted in thebore of the rotatable hollow drill bit, wherein the rod extends throughthe bore of the rotatable hollow drill bit to the tip of the needle. 21.A medication injection device comprising: a housing for grasping by anoperator, wherein the housing has a distal end; a rotatable hollow drillbit mounted to the distal end of the housing, wherein the drill bitincludes a bore therethrough, and wherein the drill bit is suitable forintraosseous drilling; means disposed in the housing for rotating thedrill bit; and fluid dispensing means including a fluid reservoirstationarily mounted in the housing and means for supplying a controlleddose of medication fluid for intraossaous injection through the bore ofthe drill bit.
 22. A device as recited in claim 21 wherein the fluiddispensing means supplies the medication fluid to the bore of the drillbit while the drill bit is rotating.
 23. A medication injection deviceas defined in claim 21, wherein the hollow drill bit includes ahypodermic needle having a sharpened point.